The invention relates to a method for synthesizing an engine noise, in particular of an internal combustion engine, as well as to a device for carrying out the method.
Several methods for generating synthetic engine noises are generally known to supplement in particular an existing engine noise of a motor vehicle so as to produce in combination a pleasing engine sound. For that purpose, electric transducer signals are generated as signal values which are fed to at least one installed electromechanical transducer, in particular an actuator or loudspeaker.
In such a method (DE 690 23 133 T3), an existing engine noise is supplemented by a produced additional sound to provide a pleasing engine sound in the interior. The state of the engine and its actual engine noise is determined by a microphone and/or a vibration sensor disposed at the engine and via a load signal. Vehicle operating noises, e.g. a sport sound, commensurate with the determined state of the engine are read out from a sound memory and made audible in the passenger compartment in addition to the actual engine noise, using loudspeakers or electrodynamic actuators. The sensor signals required for reading out the sound memory are complex and cannot be readily used to address the sound memory.
Another method for supplementing an engine noise of a motor vehicle is known (DE 10 2005 012 463 B3), wherein level values, which each correspond to a defined engine rotation speed and whose associated vibrations having orders corresponding to a multiple of half the motor rotation speed, are stored in a data memory of a control unit in a characteristic diagram at speed interpolation points. At a particular motor rotation speed, lever values of several orders associated with the particular motor rotation speed are read out and transmitted to a processor of the control unit for computing as an actuator excitation signal a continuous time signal in form of a harmonic series. This method is based on a harmonic approach, wherein several harmonics are superimposed and wherein each harmonic component has a level curve as a function of the rotation speed. This type of superposition method necessitates high expenditures for creating a desired synthetic engine sound.
Another known method (10 2007 055 477 A1) addresses the formation of signal samples having certain segment lengths. Different segment sections are used within the segment lengths to allow intentional adjustment of sound features as control parameters in combination with the possible addition of well proportioned higher harmonic components. Accordingly, this is directed to a method for composing sound designs. For adaptation to an actual motor rotation speed, these created signal samples are repeated and compressed at higher rotation speeds or stretched at lower rotation speeds. This type of rotor speed adjustment is complex; moreover, the possibilities for producing different sounds with manageable data sets are limited.
It is therefore an object of the invention to propose a method for synthetically generating engine noises which allows generation of a variety of different engine sounds with greater clarity from a minimum of data.